Anxiety. Buspirone is an anxiolytic drug. This means that it is used to treat anxiety. Common side effects include: dizziness, drowsiness, nausea and insomnia . It does not prompt tolerance or addiction and is most useful/ well-tolerated when initiated at very low doses, i.e., 1.25-2.5 mg bid. Generalized anxiety is ubiquitous. If you identify with being a "worrywart, " you may have it.